fix-broken-utf8-encodings

Sometimes, encoding issues happen and you end up with sequences of improperly escaped unicode code units in your JSON. For example, the string

"Don\\u00e2\\u0080\\u0099t forget to drink your Ovaltine."

which will decode as

"Don’t forget to drink your Ovaltine."

This occurs because the original string was encoded as UTF-8, but the JSON was encoded incorrectly (usually Latin-1 or ASCII).

The string should be encoded in JSON as

"Don\\u2019t forget to drink your Ovaltine."

or simply

"Don’t forget to drink your Ovaltine."

(note the fancy apostrophe).

This small library provides a function which will make a best-effort attempt to reinterpret these broken sequences into their original unicode control points.

Usage

const {reinterpret} = require("fix-broken-utf8-encodings");

// simply call reinterpret on your broken string
reinterpret("Don\\u00e2\\u0080\\u0099t forget to drink your Ovaltine.");
// returns "Don\\u2019t forget to drink your Ovaltine."

Additionally, there is a convenience method unescape which will both reinterpret and convert the escaped unicode code points into their actual unicode characters.

const {unescape} = require("fix-broken-utf8-encodings");
unescape("Don\\u00e2\\u0080\\u0099t forget to drink your Ovaltine.");
// returns "Don’t forget to drink your Ovaltine."

but usually you'll want to use reinterpret and then JSON.parse the result, if you are interpreting a JSON string.

Caveats

Since it's difficult to know when a series of code units is intentional or a manifestation of this encoding issue, this library only attempts to fix sequences of at least three one-byte code units. This means that it will fix sequences like

"\\u00e2\\u0080\\u0099"; // fancy apostrophe
"\\u00f0\\u009f\\u008e\\u00bb"; // violin emoji

but not sequences like

"\\u0020"; // space
"\\uD834\\uDF06"; // violin utf-16 surrogate pair
"\\uD834\\uDF06\\uD834\\uDF06"; // two violin utf-16 surrogate pairs (won't be modified since these are not one-byte code units)

Additionally, this library does not make an effort to find and fix unicode sequences which are not escaped, since it's difficult to know in general when sequences of characters are intentional.

License

MIT